It's more that we use the names a ton, for example here in Texas (as well as a few other places) we say "coke" for any kind of soda/pop/fizzy drink. I personally hate Coca-Cola, but often would ask for a coke at a restaurant, and then fill it with Dr Pepper.

Well, that's why I don't say I'll have a coke when I'm at a restaurant with a waiter. I mean if I have access to the dispenser, I'll ask for a cup for coke instead of for a soda. If I have a waiter I ask if they have a specific type of coke/soda/pop like Dr Pepper and if they do I say "Alright, then I'll have a Dr Pepper."

Well let me tell you a story about a little country called Costa Rica.

A few dozen years back, there was a brand of paint thinner, which slogan was "The best you can find". Yep, their slogan was in english in a Spanish speaking country in which almost nobody spoke English at the time. People started calling it "Canfín", derivated from their slogan's "can find".

So, to this day, any brand of paint thinner here is called Canfín. In fact, the substance itself is called Canfin (pronounced can-fin (fin like the ones on fish)).

The same happened with the chewing gum brand Chiclets. Now, you buy "chicles", not chewing gum (or "goma de mascar" on most other spanish speaking countries).